Various grains find universal use and appeal when processed into food products. These products may be manufactured in large volume a considerable time after harvesting the grain. The grain must therefore be stored during the time lapse between harvesting and processing. Storage under refrigerated conditions is not practical, the amount of refrigeration storage space often being severely limited or not available at all. Moreover, refrigerated storage of large volumes of grain is unduly expensive and consumes an extensive amount of energy.
High moisture grain stored at ambient temperatures is severely subject to mold and yeast growth. Grain, because it grows in a natural environment, is heavily contaminated with a wide variety of types of molds and yeasts when harvested. Spores of mold and yeast are also contained in the atmosphere. Within four days to two months after harvest, grain stored at ambient temperatures, typically, 70.degree. to 80.degree. F., is subject to mold growth. Mold growth, of course, precludes processing of grain into food products.
Chemical preservatives such as propionic acid and acetic acid have been known to retard mold and yeast growth on high moisture grain, but it is an expensive preservative agent and use of such preservatives necessitates treating the inside of the storage bins to prevent damage from corrosion.
Drying grain has long been recognized as a means for reducing mold and yeast growth. The most common method used today is drying by natural gas. Now, in an age of energy shortage, a method for reducing spoilage not dependent upon a high energy requirement would be advantageous. Additionally, the most convenient drying apparatus, a storage bin with a self-contained drying unit, requires a large capital investment. Reduction of moisture content of grain has also been accomplished by exposure of the grain to the sun's radiant energy prior to storage. This method has the disadvantage of being weather dependent. Even locations with normally good climatic conditions for grain drying are subject to the whims of the weather.
The use of ethyl alcohol to retard mold spoilage of packaged pizza crusts is known from U.S. Pat. No. 3,979,525. Pizza crusts are composed essentially of wheat flour which has been subjected to vigorous processing which reduces the fat, fiber and protein content as compared to unprocessed high moisture grain. The problems of preserving two very different commodities such as pizza crusts and high moisture grain are not surprisingly very different also. Pizza crusts have very little yeast and mold contamination because the baking process essentially kills all yeast and mold contamination and the only contamination of concern is that occuring after baking. For instance, a typical mold and yeast count for pizza crusts is less than 10 per gram of product as compared to a mold and yeast count of 100,000 per gram of high moisture grain. These two commodities are also subject to attack by different types of mold. Pizza crust have a tendency to spoilage from growth of penicillium mold. For high moisture grain however, suitable protection against growth of aspergillus mold is the problem presented upon storage.
Accordingly, it is a principal object of the invention to reduce the spoilage of high moisture grain resulting from mold growth and yeast growth. It is an object to reduce the spoilage of high moisture grain that has not been processed prior or during storage to remove a substantial amount of moisture for preservative purposes.
It is another object of the present invention to provide a method for reducing spoilageof grain resulting from mold growth without the necessity of reduction of moisture content or refrigeration.
It is still another object of the invention to reduce spoilage of high moisture grain resulting from mold growth by using inexpensive methods which meet legal and industrailly accepted standards.
These and further objects of the invention will be apparent from the following description, appended drawings, and attached claims.